It is misleading to refer to the US prison system as privatized, when the percentage of the total inmates that are in private prisons is only around 3% [1].
Privatized prisons do create a huge moral hazard, but currently the pro-prison groups with the biggest scope and influence are probably police/guard unions [2] and the "tough on crime" crowd.
Those two groups still profit from prisons, regardless of whether the prisons themselves are privatized. Perhaps it's best to speak of prison profits and interests which exist in every prison and lead to the same problems as privatized prisons. Not to mention other profiting industries like the phone company who handles all the collect calls, equipment manufacturers, etc.
Bottom line is, it pays to send and keep people in prison regardless if the prisons themselves are privatized.
So the phone companies are in on it too? Maybe the problem is people commit crimes? Most crimes go unsolved. How many crimes happen before they are actually caught.
So, comparing US incarceration stats with other countries, would you then say the average US citizen is more likely to commit crime than other nationalities?
Bottom line is, it pays to send and keep people in prison regardless if the prisons themselves are privatized.